IAEA: Iran worked on developing nuclear weapons
Iran took limited steps towards developing a nuclear bomb in the past, the global nuclear watchdog has said.
But the report from the IAEA said the efforts did not go beyond planning and testing of basic components.
Iran's Deputy Foreign Minister Abbas Araqchi said the findings confirmed that Tehran's nuclear programme was peaceful.
The report was a condition of this year's landmark deal between Iran and six world powers.
The July agreement involves the lifting of sanctions in return for Iran curbing sensitive nuclear activities.
In its report, the IAEA said most of the "co-ordinated" work by Iran took place before 2003, with some activities continuing up to 2009.
But it added "these activities did not advance beyond feasibility and scientific studies, and the acquisition of certain relevant technical competences and capabilities".
The report will now be forwarded to the IAEA's board for discussion later in December.
Iran has long insisted its nuclear activities are peaceful and warned it would not implement parts of the nuclear accord unless the IAEA's investigations into whether its programme had military aspects were closed.
The US state department said the report "adequately addressed outstanding questions on the past military dimensions of Iran's nuclear programme".
Spokesman Mark Toner said the nuclear accord would provide enough transparency and access to ensure there would be no repeat of Tehran's activities.
Key areas of the nuclear deal:
Uranium enrichment: Iran can operate 5,060 first generation centrifuges, configured to enrich uranium to 3.67%, a level well below that needed to make an atomic weapon. It can also operate up to 1,000 centrifuges at its mountain facility at Fordow - but these cannot be used to enrich uranium.
Plutonium production: Iran has agreed to reconfigure its heavy water reactor at Arak, so that it will only produce a tiny amount of plutonium as a by-product of power generation, and will not build any more heavy water reactors for 15 years.
Inspections: International monitors will be able to carry out a comprehensive programme of inspection of Iran's nuclear facilities.
Sanctions: All EU and US energy, economic and financial sanctions, and most UN sanctions, will be lifted on the day Iran shows it has complied with the main parts of the deal.